KR20170066637A - Brazing sheet - Google Patents

Abstract

In one embodiment, the brazing sheet comprises a core layer, a braze liner on the first side of the core layer, and a water side liner on the second side of the core layer. The core layer is made of 3xxx series aluminum alloy. Said water side liner comprising 7 to 20% by weight of Zn; 0.25 wt% or less of Si; Not more than 0.1% Cu; No more than 0.25 wt% Mn; 0.1% or less Mg; And 0.1% by weight or less of Cr. In some embodiments, the brazing sheet has a thickness of 60 to 180 microns. In some embodiments, the water side liner occupies 1 to 15% of the thickness of the braze sheet.

Description

Brazing Sheet {BRAZING SHEET}

The present invention relates to a brazing sheet.

relation Cross reference to application

This application claims priority from U.S. Provisional Patent Application No. 62 / 063,267, filed October 13, 2014, the entirety of which is incorporated herein by reference.

Heat exchangers, such as radiators and heater cores, are used to transfer thermal energy from an operating system, such as an automobile engine, to the surrounding environment. A coolant or cooling fluid is used as a medium to send heat from the operating system to the heat exchanger. Depending on the chemical additive, the coolant may cause corrosion on the aluminum tube used in the heat exchanger. Thus, a braze sheet product for this type of heat exchanger application, such as a tubestock or header plate, has a liner (called a waterside liner) on the coolant side, which provides corrosion protection to the core of the aluminum tube to provide.

In one embodiment, the brazing sheet comprises a core layer, a braze liner on the first side of the core layer, and a water side liner on the second side of the core layer. The core layer is made of 3xxx series aluminum alloy. Said water side liner comprising 7 to 20% by weight of Zn; 0.25 wt% or less of Si; Not more than 0.1% Cu; No more than 0.25 wt% Mn; 0.1% or less Mg; And 0.1% by weight or less of Cr.

In some embodiments, the water side liner comprises 7 to 20 wt% Zn; 0.25 wt% or less of Si; Not more than 0.1% Cu; No more than 0.25 wt% Mn; 0.1% or less Mg; And up to 0.1 wt% Cr, and the balance aluminum, incidental elements and impurities.

In some embodiments, the water side liner comprises 10 to 20 weight percent Zn. In some embodiments, the water side liner comprises 12 to 20 wt% Zn. In some embodiments, the water side liner comprises 15 to 20 wt% Zn. In some embodiments, the water side liner comprises from 16 to 20% by weight of Zn. In some embodiments, the water side liner comprises 9-12 wt% Zn.

In some embodiments, the core layer comprises 0.5-1.25 wt% Si; 0.5 to 1.25 wt% Cu; 0.5 to 2.0 wt% Mn; 0.15 wt% or less Mg; 0.1% Cr or less; 0.1 wt% or less of Zn, and 0.1 to 0.2 wt% of Ti.

In some embodiments, the core layer comprises 0.5 to 1.25 wt% Si; 0.5 to 1.25 wt% Cu; 0.5 to 2.0 wt% Mn; 0.15 wt% or less Mg; 0.1% Cr or less; 0.1 wt% or less of Zn, 0.1 to 0.2 wt% of Ti, and the balance of aluminum, incidental elements and impurities.

In some embodiments, the braze liner comprises a 4xxx series aluminum alloy.

In some embodiments, the brazing sheet has a thickness of 60 to 180 microns. In some embodiments, the brazing sheet has a thickness of 60 to 150 microns. In some embodiments, the brazing sheet has a thickness of 80 to 150 microns. In some embodiments, the brazing sheet has a thickness of 60 to 100 microns. In some embodiments, the brazing sheet has a thickness of 60 to 180 microns.

In some embodiments, the brazing sheet has a thickness, and the water side liner occupies 1 to 15% of the thickness. In some embodiments, the brazing sheet has a thickness, and the water side liner occupies 7 to 15% of the thickness. In some embodiments, the brazing sheet has a thickness, and the water side liner occupies 7 to 10% of the thickness. In some embodiments, the brazing sheet has a thickness, and the water side liner occupies 5 to 15% of the thickness. In some embodiments, the brazing sheet has a thickness, and the water side liner occupies 5 to 10% of the thickness.

In one embodiment, the brazing sheet comprises a core layer, a braze liner on the first side of the core layer, and a zinc layer on the second side of the core layer. The core layer is made of 3xxx series aluminum alloy.

In some embodiments, the zinc layer comprises 99.9 wt% Zn.

In some embodiments, the brazing sheet has a thickness, and the zinc layer accounts for less than 2% of its thickness.

In some embodiments, the core layer comprises 0.5 to 1.25 wt% Si; 0.5 to 1.25 wt% Cu; 0.5 to 2.0 wt% Mn; 0.15 wt% or less Mg; 0.1% Cr or less; 0.1 wt% or less of Zn, and 0.1 to 0.2 wt% of Ti.

In some embodiments, the core layer comprises 0.5 to 1.25 wt% Si; 0.5 to 1.25 wt% Cu; 0.5 to 2.0 wt% Mn; 0.15 wt% or less Mg; 0.1% Cr or less; 0.1 wt% or less of Zn, 0.1 to 0.2 wt% of Ti, and the balance of aluminum, incidental elements and impurities.

In some embodiments, the brazing sheet has a thickness of 60 to 180 microns. In some embodiments, the brazing sheet has a thickness of 60 to 150 microns. In some embodiments, the brazing sheet has a thickness of 80 to 150 microns. In some embodiments, the brazing sheet has a thickness of 60 to 100 microns. In some embodiments, the brazing sheet has a thickness of 60 to 180 microns.

Those skilled in the art will appreciate that the disclosed braze sheet may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings, which serve to illustrate, at least, various features of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view of one embodiment of a brazing sheet.
Figure 2 is a schematic cross-sectional view of another embodiment of a brazing sheet
3 is a schematic cross-sectional view of another embodiment of the brazing sheet.
4 is a schematic cross-sectional view of another embodiment of a brazing sheet.
5 is a graph showing the simulated pre-braze zinc distribution according to a conventional brazing sheet.
Figure 6 is a graph showing the simulated pre-braze zinc distribution according to another embodiment of the brazing sheet.
Figure 7 is a graph showing simulated pre-braze zinc distribution according to another embodiment of a brazing sheet.
8 is a graph showing simulated pre-braze zinc distribution according to another embodiment of the brazing sheet.
9 is a graph showing the simulated post-braze zinc distribution according to the prior art referred to in Fig.
FIG. 10 is a graph showing the post-simulated braze post-zinc distribution according to the embodiment referred to in FIG.
11 is a graph showing the post-simulated braze post-zinc distribution according to the embodiment referred to in Fig.
12 is a graph showing the post-simulated braze post-zinc distribution according to the embodiment referred to in Fig.
13 is a chart showing the difference in zinc concentration between the liner and the core of the embodiment referred to in Figs. 5-12. Fig.
14 is a graph showing the simulated pre-braze zinc distribution of four additional embodiments.
15 is a graph showing the simulated braze pre-copper distribution of the four embodiments referred to in Fig.
16 is a graph showing the simulated pre-braze pre-silicon distribution of the four embodiments referred to in Fig.
Figure 17 is a graph showing the post-simulated braze post-zinc distribution of the four embodiments mentioned in Figure 14;
18 is a graph showing the copper distribution after the simulated braze of the four embodiments mentioned in Fig.
19 is a graph showing the silicon distribution after simulated braze of the four embodiments referred to in Fig.
Figure 20 shows the characteristics of two embodiments of the brazing sheet.
21 shows the zinc distribution of the two embodiments illustrated in FIG.
Fig. 22 shows the results of the OY corrosion test in the two embodiments illustrated in Fig.
Figure 23 shows a sample according to both embodiments shown and described in Figures 21 and 22 after completion of the immersion test.
Fig. 24 shows the sample of Fig. 23 after completion of the immersion test for 60 days.

Those skilled in the art will appreciate that the disclosed braze sheet may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings, which serve to illustrate, at least, various features of the present disclosure.

1 shows a brazing sheet according to one embodiment. The core layer 12 comprising a 3xxx series aluminum alloy has a braze liner 16 on the first side and a water side liner 14 on the second side.

In some embodiments, the core layer comprises 0.5 to 1.25 wt% Si, 0.5 to 1.25 wt% Cu, 0.5 to 2.0 wt% Mn, 0.1 wt% or less Mg, 0.15 wt% or less of Cr, 0.1 wt% or less of Zn, To 0.2% by weight, the balance of Al and unavoidable impurities.

In some embodiments, the water side liner comprises 7 to 20 wt% Zn, 0.25 wt% or less of Si, 0.1 wt% or less of Cu, 0.25 wt% or less of Mn, 0.1 wt% or less of Mg, 0.1 wt% or less of Cr and unavoidable impurities .

In some embodiments, the braze liner comprises a 4xxx series aluminum alloy.

Figure 2 shows a brazing sheet according to another embodiment. A second liner 22 is shown between the braze liner 16 and the core layer 12.

Figure 3 shows a brazing sheet according to another embodiment. The core layer 12 comprising a 3xxx series aluminum alloy has a braze liner 16 on the first side and a water side liner 32 on the second side. In this embodiment, the water side liner can be Zn of 99.9 wt% Zn and commercial purity containing unavoidable impurities. The layer may be applied on the second side of the core using a zinc spray process, casting / rolling the layer on the second side of the core using a coating process, or on the second side of the core .

The embodiment shown in FIG. 4 includes a second layer 42 of commercial purity zinc between the core layer and the braze liner 16.

In some embodiments of the brazing sheet shown in Figure 2, the second liner 22 comprises zinc of commercial purity (99.9 wt%).

Since the zinc in the aluminum lowers the melting point of the Al-Zn alloy, there may be a risk of melting the high zinc-containing layer before or at the braze temperature around 600 ° C in the brazing process. However, zinc in the water side liner can be redistributed through the manufacturing process by being diffused from the water side liner to the core, which reduces the initial zinc concentration in the water side liner and thus allows the water side liner to undergo a hot brazing process without melting . The manufacturing process may be any thermal or mechanical process known in the art for producing a brazing sheet, such as annealing, hot rolling, and cold rolling. The amount of zinc diffusion to occur will depend on factors known to those skilled in the art, such as this type of process step, time and temperature.

Examples of the distribution of zinc in a 150 micron brazing sheet according to one embodiment performed prior to and prior to proceeding with the fabrication process are shown in Figures 5 through 8 (these graphs merely show that from the middle thickness of the brazing sheet to the water side, That is, 75 to 150 microns). Figure 5 shows the zinc distribution in the brazing sheet with a prior art water side liner starting with 4.6 wt% Zn. Figure 6 shows the zinc distribution in the brazing sheet with a water side liner starting with 12 wt% Zn. Figure 7 shows the zinc distribution in the brazing sheet with a water side liner starting with 16 wt% Zn. Figure 8 shows the zinc distribution in the brazing sheet with a water side liner starting with 99.5 wt% Zn. 5 to 8 show the thickness of the brazing sheet at which the core layer ends and the water side liner starts. The higher the zinc concentration in the water side liner, the thinner the water side liner can still provide adequate protection to the core. This allows the core to be thicker and maintains the same thickness of the brazing sheet while providing a higher strength to the brazing sheet.

Zinc distribution after brazing is shown in Figures 9-12. Figure 9 shows the post-braze zinc distribution in a brazing sheet having a prior art water side liner starting with 4.6 wt% Zn. Figure 10 shows the post-braze zinc distribution in a brazing sheet having a water side liner starting with 12 wt% Zn. Figure 11 shows the post-braze zinc distribution in a brazing sheet having a water side liner starting with 16 wt% Zn. Figure 12 shows the post-braze zinc distribution in a brazing sheet having a water side liner starting with 99.5 wt% Zn.

The difference in zinc level between the liner surface and the core is tabulated in Fig. The zinc levels shown in the table indicate that the initial zinc levels are significantly reduced through thermal and mechanical treatments depending on the corresponding clad ratio: from 99.5% to 11.345%, from 16% to 8.735 %, From 12% to 8.179%, and from 4.6% to 4.357%. In this way, the risk of melting in the brazing process is significantly reduced, which makes it possible to use high-concentration zinc-containing alloys for water-side liner applications.

The simulated zinc distribution also shows that for a high concentration zinc containing liner a low cladding ratio can provide a greater difference in zinc levels between the liner surface and tube center for the material after brazing, Is expected to provide better corrosion protection to the tube formed by the brazing sheet according to the embodiment.

Some embodiments provide high strength and improved corrosion protection capabilities to enable light gauge products.

In another example, one embodiment of a 100 micron thick brazing sheet is used as a radiator / heater core tube. Figures 14-16 show zinc, copper and silicon distributions, respectively, before brazing, before proceeding with the fabrication process. Figure 14 shows the zinc distribution in the brazing sheet with a water side liner starting with 4.6 wt% Zn, 12 wt% Zn, 16 wt% Zn and 99.5 wt% Zn. The water side liner accounts for 30% of the thickness of the brazing sheet with the water side liner starting with 4.6 wt% Zn (prior art). The water side liner accounts for 10% of the thickness of the brazing sheet with the water side liner starting with 12 wt% Zn. The water side liner occupies 7.5% of the thickness of the brazing sheet with a water side liner starting with 16 wt% Zn. The water side liner accounts for 1% of the thickness of the brazing sheet with a water side liner starting with 99.5 wt% Zn.

15 shows the copper distribution in a brazing sheet having a water side liner starting with 4.6 wt% Zn, 12 wt% Zn, and 16 wt% Zn. Figure 16 shows the silicon distribution in a brazing sheet having a water side liner starting with 4.6 wt% Zn, 12 wt% Zn, and 16 wt% Zn.

The alloying element distribution of the material after brazing is shown in the graphs of FIGS. Fig. 17 shows the zinc distribution, Fig. 18 shows the distribution of copper, and Fig. 19 shows the silicon distribution.

The vertical lines in Figures 14-19 show the thickness of the brazing sheet at which the core layer ends and the water side liner begins.

Four liner thicknesses with four zinc levels are shown in Figures 14-19. For high zinc levels, a low cladding ratio can be used to provide sufficient corrosion protection to the tube formed of the brazing sheet according to some embodiments.

The diffusion simulation shows that a water side liner having a relatively higher zinc concentration and a lower clad ratio has a higher zinc concentration and a lower clad ratio than the water side liner having a relatively lower zinc level and a higher clad ratio, It is possible to generate a concentration difference. Larger zinc concentration differences can provide better corrosion protection to the core. The low cladding ratio enables thicker core thickness, which aids in increasing the strength of the tubing.

In some embodiments, a zinc containing liner comprising one of the disclosed alloys is positioned on the first side of the core between the braze liner and the core to provide corrosion protection on the air side of the brazing sheet.

Figure 20 shows the characteristics of a laboratory-fabricated heater core tube made of a brazing sheet according to both embodiments. Both embodiments have a thickness of about 0.1 mm. The clad ratio of the braze liner was about 20%, and the clad ratio of the water side liner was about 11%. The braze liners in both embodiments were composed of the same alloy. The water side liner in both embodiments was composed of the same alloy. Two different core alloys have been tested.

FIG. 21 shows the zinc distribution of the two embodiments illustrated in FIG. 21. FIG. In connection with both of the above embodiments, zinc has diffused into the core in the manufacturing process, but the gradient of zinc diffusion is still steep. The difference in zinc levels between the water side liner and the core is significant and produces an excellent corrosion potential difference so that in both embodiments the water side liner can provide adequate corrosion protection to the core.

The results of the OY corrosion test are shown in Fig. The sample shown suffered an OY corrosion test for 250 hours. The OY test temperature was 95 캜 and a flow rate of about 1 liter / min was used. The composition of the OY solution is as follows:

Figure 23 shows a sample according to both embodiments shown and described in Figures 21 and 22 after completion of the immersion test. Corrosion attack is only on the water liner. The cores were not corroded.

Fig. 24 shows the sample of Fig. 23 after completion of the immersion test for 60 days.

The brazing sheet is a metal sheet having a plurality of discrete layers, including at least one braze liner or layer.

The braze liner is a layer of a brazing sheet comprising braze material.

The core layer is one layer of the brazing sheet. The core layer has a first side and a second side. The braze liner is positioned on one side or both sides of the core layer. The braze liner may be directly on the core layer or there may be an intermediate liner between the core and the braze liner.

The water side liner is a layer of a brazing sheet on one side of the core layer. The purpose of the water side liner is to protect the core from corrosion caused by the coolant flowing through the interior of the tube of braze sheet.

As used herein, "incidental element" means an element or material that can be optionally added to an alloy to assist in the manufacture of the alloy. Examples of additional elements include casting aids such as grain refiners.

A grain refiner is an inoculant or nuclei for seeding new grain during solidification of the alloy. An example of a grain refiner is a 9.5 mm (3/8 inch) rod comprising 96% aluminum, 3% titanium (Ti), and 1% boron (B), where virtually all boron And is present as dispersed TiB ₂ particles. During casting, the grain refining rod is fed inline to the molten alloy entering the casting pit at a controlled rate. The amount of grain refiner present in the alloy generally depends on the type of material used in the grain refining and alloy manufacturing process. Examples of grain refiners include Ti (TiB ₂ ) in combination with B or Ti (TiC) in combination with carbon, although other grain refiners such as Al-Ti master alloys may be used. Generally, grain refiners (e. G., Boron) may be added to the alloy in amounts ranging from 0.0003% to 0.03% by weight, depending on the desired size of the casted grain. Further, Ti may be added to the alloy in an amount of 0.03 wt% or less to increase the efficiency of the grain refiner. Ti, when included in the core alloy, is generally present in an amount of up to about 0.10 or 0.20 wt%.

Ancillary elements may be present in minor amounts or may be present in significant amounts and may add inherently desirable or other properties without departing from the alloy described herein if the alloy retains the desired properties described herein . It should be understood, however, that the scope of the present invention, which simply adds elements or elements in amounts that do not affect the combination of properties desired and desired herein, should not be avoided (can not be avoided).

As used herein, "impurities" are materials that may be present in the alloy in trace amounts, for example due to the inherent characteristics of aluminum and / or from contact with the manufacturing equipment. Iron (Fe) is an example of impurities generally present in aluminum alloys. The Fe content of the alloy generally does not exceed about 0.25 wt%. In some embodiments, the Fe content of the alloy does not exceed 0.15 wt%, does not exceed 0.10 wt%, does not exceed 0.08 wt%, or does not exceed 0.05 wt% or 0.04 wt%.

The alloys and temperers referred to herein are defined by the American Institute of Standards and Alloy naming and chemical composition restrictions for aluminum alloys and forged aluminum alloys amended in 2015 and the American Standard Alloy and Tempering System for aluminum ANSI H35.1 Respectively.

Except as otherwise stated, the expression "below " means, when referred to in connection with an elemental amount, that the elemental composition is optional or ancillary and thus includes zero amounts of particular compositional components. Unless otherwise stated, all compositions are percent by weight (wt%).

Claims (20)

a. (i) 3xxx series aluminum alloy; (ii) a first side; (iii) a core layer comprising a second side,
b. A braze liner on the first side of the core layer, and
c. A waterside liner on the second side of the core layer,
A brazing sheet comprising:
The water-
(i) 7 to 20% by weight of Zn;
(ii) not more than 0.25 wt% Si;
(iii) not more than 0.1% Cu by weight;
(iv) no more than 0.25 wt% Mn;
(v) 0.1% or less Mg; And
(vi) not more than 0.1 wt% Cr
Wherein the brazing sheet is an aluminum alloy. The method according to claim 1,
The water-
a. 7 to 20% by weight of Zn;
b. 0.25 wt% or less of Si;
c. Not more than 0.1% Cu;
d. No more than 0.25 wt% Mn;
e. 0.1% or less Mg;
f. 0.1% Cr or less; And
g. The remaining amount of aluminum, incidental elements and impurities
And a brazing sheet. The method according to claim 1,
Wherein said water side liner comprises 10 to 20 weight percent Zn. The method according to claim 1,
Wherein the water side liner comprises 12 to 20 weight percent Zn. The method according to claim 1,
Wherein said water side liner comprises 9-12 wt% Zn. The method according to claim 1,
Wherein the water side liner comprises 16 to 20 wt% Zn. The method according to claim 1,
The core layer
a. 0.5 to 1.25 wt% Si;
b. 0.5 to 1.25 wt% Cu;
c. 0.5 to 2.0 wt% Mn;
d. 0.15 wt% or less Mg;
e. 0.1% Cr or less;
f. 0.1% by weight or less of Zn; And
g. 0.1 to 0.2% by weight of Ti
And a brazing sheet. The method according to claim 1,
The core layer
a. 0.5 to 1.25 wt% Si;
b. 0.5 to 1.25 wt% Cu;
c. 0.5 to 2.0 wt% Mn;
d. 0.15 wt% or less Mg;
e. 0.1% Cr or less;
f. 0.1% by weight or less of Zn;
g. 0.1 to 0.2% by weight of Ti; And
h. The remaining amount of aluminum, incidental elements and impurities
And a brazing sheet. The method according to claim 1,
Wherein the brazing sheet has a thickness of 60 to 180 microns. The method according to claim 1,
Wherein the brazing sheet has a thickness of 60 to 150 microns. The method according to claim 1,
Wherein the brazing sheet has a thickness of 80 to 150 microns. The method according to claim 1,
Wherein the brazing sheet has a thickness of 60 to 100 microns. The method according to claim 1,
Wherein the brazing sheet has a thickness of 60 to 180 microns. The method according to claim 1,
Wherein the brazing sheet has a thickness and the water side liner occupies 7 to 15% of its thickness. The method according to claim 1,
Wherein the brazing sheet has a thickness and the water side liner occupies 7 to 10% of its thickness. The method according to claim 1,
Wherein the brazing sheet has a thickness and the water side liner occupies 5 to 15% of its thickness. The method according to claim 1,
Wherein the brazing sheet has a thickness and the water side liner occupies 5 to 10% of its thickness. a. (i) 3xxx series aluminum alloy; (ii) a first side; (iii) a core layer comprising a second side,
b. A braze liner on the first side of the core layer, and
c. A zinc layer on the second side of the core layer
≪ / RTI > 19. The method of claim 18,
Wherein the zinc layer comprises 99.9 wt% Zn. 19. The method of claim 18,
Wherein the brazing sheet has a thickness and the zinc layer occupies less than 2% of its thickness.

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